Sonoma difficulty in handling 2nd external monitor

Question

Level 1

6 points

Sonoma difficulty in handling 2nd external monitor

After upgrading to Sonoma on my Mac Studio M1 Ultra a week ago on a 3x 27" LG monitor set up (1xHDMI + 2x USB-C), a few days later, I suddenly see one of my 27UP850N external monitors show odd white/grey static all of a sudden. Turning the device on and off doesn't change things, and I would have to disconnect the monitor's USB-C connector and power adapter for at least more than 10 minutes before things return to normal. Tried changing the USB port and the cable used to no avail as the behavior would just repeat after a while.

Thinking that it might be a hardware issue, I purchased an inexpensive 1440p Bezel (name of the brand) USB-C monitor to test things out further. The first day was fine, but similar problems arose the next day. In one instance, it looked like the brightness on the monitor was fading in and out rapidly and unpredictably, after which a different kind of white/black random pattern suddenly materialized. Cycling the power of the monitor and waiting another 10 minutes later, the monitor recovered and worked for another few hours before a perfectly stable image suddenly turned into the previously seen pattern. I've been able to reproduce odd and varying instances of these behaviors after a period of seeing the monitor work fine for some time.

When this happens, I can't even get into the monitor menus for both monitors in question as Sonoma seems to do something that not only affects the monitor image, but also elements at the monitor's GUI level.

Here's a short video of the second monitor (Bezel 27" 1440p):

https://www.dropbox.com/scl/fi/saqdcxxhqavkqdgu0kecm/IMG_1982.MOV?rlkey=xf2c6jma85c6s05ku56co5843&dl=0

I've tried switching to every other available USB port and changing the USB cable used to no avail. I'm not certain what causes a particular external monitor to experience this while the other seems fine.

Original monitor combination:

HDMI - LG27GN950 (scaling mode, 1440p, 60hz)

external 1 (no problem) - LG27UP850N (scaling mode, 1440p, 60 hz)

external 2 (suddenly exhibited the problem) - LG27UP850N (scaling mode, 1440p, 60 hz)

Second monitor combination:

HDMI - LG27GN950 (scaling mode, 1440p, 60hz)

external 1 (no problem) - LG27UP850N (scaling mode, 1440p, 60 hz)

external 2 (also consistently experiencing the problem) - Bezel 27CX100 (native 1440p, tried 60hz to 100hz but still ran into the problem eventually)

Mac Studio (2022)

Posted on Oct 16, 2023 4:21 PM

Reply

Answer 1

Oct 30, 2023 8:19 AM in response to fonso2

Can confirm the same problem on Dell TB4 docks when the display is using HDMI and DP ports - it only shows one display in MacOS and mirrors both external displays (Dell P2217H)

At my home office I have the same dock (company has literal thousands of them at the office and all WFH). Connected are two 27" 4K LG displays, one of which uses the Type C connection and it doesn't have this issue.

Reply

Answer 2

smcca945

Level 1

8 points

Jan 31, 2024 6:31 PM in response to fonso2

I have 4 different docking stations and right after the Sonoma upgrade, my external monitors didn't work anymore. I had to try all kinds of different combinations of docking stations and display connections to get my two monitors working again. I finally have one USB C docking station working when I connect 1 monitor with HDMI and the other with DisplayPort. If I try to connect both with HDMI, nothing works. If I connect both with DisplayLink, they flicker forever and never sync. I had to do one HDMI and one DisplayPort and I finally got it working with 1 docking station.

My main docking station doesn't work no matter what I do and I can only get 1 monitor to display on the others. Sonoma is not working properly with docking stations that use DisplayLink chipsets even with the latest DisplayLink software. Even if I try to bypass the docking stations and connect the monitors via USB-C, I can only get 1 monitor to work.

Sonoma is broken right now if you are trying to get two external monitors to work unless you find the magic combination of docking stations and connections. My main docking station worked perfectly on Ventura and now doesn't work in Sonoma. Clearly there are display issues with Sonoma that need to be fixed. It's not DisplayLink or anything else - it's Sonoma.

The nice thing with Sonoma is that you can now see the machine boot on external monitors and type in your password before DisplayLink works so it looks like they fundamentally changed how the monitors are handled. I do like how the external monitors show the boot screens now which is great.

They just need to get Sonoma fixed with the external monitor issues.

Reply

Answer 3

martimz

Level 1

8 points

Feb 6, 2024 12:04 AM in response to fonso2

I also have a problem with my 2nd external monitor using Sonoma. I just updated my computer to Sonoma this weekend and the 2nd external monitor is not available anymore. I use a HyperDrive Dual docking station. I hope they fix this problem soon...

Reply

Answer 4

martimz

Level 1

8 points

Feb 6, 2024 1:04 AM in response to martimz

I was able to solve my issue by downloading and connecting the MacOS InstantView application! (Should work for the HyperDrive Dual docking station.)

Download link:

https://www.siliconmotion.com/downloads/index.html

Reply

Answer 5

ginix

Level 1

0 points

Feb 14, 2024 10:16 AM in response to fonso2

I have exactly the same problem. 3 monitors and 2 USB and 1 HDMI. The screen started like closing and reopening windows. Tried everything to make things only worse. Now mac only recognizes my DELL monitor on USB. The other 2 (HP) don't get recognized if I connect them and if they do it only shows on the three a black screen until I remove the other two.

Reply